Transmission is widely used in the field of chemical industry, textile, foodstuff, sewage cleaning, etc. There are mechanical transmissions and electronic transmissions. Most continuously variable mechanical transmissions are bell type transmissions or planetary gear type transmissions. The former tends to be damaged due to aging and fatigue of the belt. The later is larger and needs a hydraulic control device, which limits its application and also makes it tend to be damaged. A coaxial connecting rod stepless pulsating transmission was published in patent application No. CN200510132746.9, which uses an eccentric wheel with a slanting cylindrical profile, wherein the side periphery of the eccentric wheel is jacketed with a slide ring which has a center bore corresponding to the outer shape of the slanting cylindrical eccentric wheel, i.e., the center bore is a slant bore with the same gradient as the slanting cylindrical eccentric wheel. When the bottom of the slanting cylindrical eccentric wheel is concentric with the input shaft, zero variable ratio change can be achieved. This transmission has overcome some shortages in the prior art, such as being complex and huge, expensive in view of manufacturing cost, inconvenient to maintain, and difficult in changing rotational speed ratio. This transmission not only has simple and compact configuration, but also is low in manufacturing cost and convenient to maintain. More importantly, it can provide very low minimal rotational speed ratio change, such as zero, so its ratio can vary from zero to maximal design value. Moreover, it may change speed not only in stopping state, but also in operating state. However, its pulsating magnitude varies with the number of connecting rods. The smaller the desired pulsating magnitude is, the more the required connecting rods are, and conversely, the larger the desired pulsating magnitude is, the less the required connecting rods are. It is, however, impossible to set too many connecting rods considering its configuration, which imposes limit when smaller pulsating magnitude is needed.